<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>京东三角盒子</title>
    <style>
        .cfx {
            position: relative;
            width: 120px;
            height: 249px;
            margin-top: 300px;
            background-color: pink;
        }

        .sjx {
            position: absolute;
            right: 15px;
            top: -20px;
            width: 0;
            height: 0;
            border: 10px solid transparent;
            border-bottom-color: pink;
        }
    </style>
</head>

<body>
    <div class="cfx">
        <div class="sjx"></div>
    </div>

</body>

</html>